RazorViewEngine does not use the right view expander when invalid culture is passed in mono.

[sornaks]

https://github.com/aspnet/Mvc/blob/dev/test/Microsoft.AspNet.Mvc.FunctionalTests/ViewEngineTests.cs#L146

[sornaks]

This is because in Linux and Windows 10 the CultureInfo constructor does not throw when an invalid culture is passed with the contents matching the string constraints. Changed na to !-invalid-! and it fails appropriately.

[sornaks]

For the following test:
https://github.com/aspnet/Mvc/blob/dev/test/Microsoft.AspNet.Mvc.FunctionalTests/ViewEngineTests.cs#L304

This is the failure:

Microsoft.AspNet.Mvc.FunctionalTests.ViewEngineTests.RazorViewEngine_UsesExpandersForLayouts(value: "!-invalid-!", expected: "<language-layout>\nView With Layout\n</language-layo"...) [FAIL]
      Assert.Equal() Failure
                 ↓ (pos 1)
      Expected: <language-layout>\nView With Layout\n</langu···
      Actual:   <fr-language-layout>\nView With Layout\n</fr···
                 ↑ (pos 1)
      Stack Trace:
           at Microsoft.AspNet.Mvc.FunctionalTests.ViewEngineTests+<RazorViewEngine_UsesExpandersForLayouts>d__22.MoveNext () [0x00000] in <filename unknown>:0 
         --- End of stack trace from previous location where exception was thrown ---
           at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0